1. Field of the Invention
This invention relates to a method and apparatus for moving on land a large self-elevating structure such as a mobile sea oil drilling platform. Many mobile sea oil drilling platforms are constructed at locations which have facilities, such as ramps or inclined ways, for sliding the completed platform into the water for launching. However, in areas subject to wide changes in shore line and water depth, such as large rivers and shallow tidal areas, inclined launched ways are impractical. This invention finds particular utility at mobile sea oil drilling platform construction locations where launch ways cannot be used and provides an apparatus whereby the platform is rendered self-mobile as well as a method of moving the platform employing the apparatus.
2. The Prior Art
Inclined launch ways cannot be used to launch a completed mobile offshore oil drilling platform where the shoreline location is subject to wide variance due to tides or river levels. One previous launching system employed at such a location, on the Mississippi river, employed bull-dozers to build a large pile of dirt under the rear portion of the body of the elevated platform. The legs of the platform were then adjusted to pivot the platform forward on the dirt pile; after which the body of the platform would be raised, the bull-dozers would move the pile of dirt forward so the platform could be pivoted forward again. Prior to each pivoting operation the dirt pile would have to be packed several times by resting the weight of the platform on the pile before it would be in a condition to permit the platform to be pivoted upon it.
The use of such procedure to launch the completed platform was extremely tedious and expensive requiring the continuous use of several pieces of special earth moving equipment and attendants for as much as 2 weeks.